It is known from DE 25 49 790 to introduce a liquid into the suction-intake air of the compressor, upstream of the compressor, in order to increase the power output of a gas turbine group. The injected liquid mass flow is in this case dimensioned from case to case in such a way that, in addition to a first part mass flow, which evaporates upstream of the compressor in the suction-intake air, a further part mass flow penetrates as liquid into the compressor. The liquid cools, on the one hand, due to the evaporation of the suction-intake air, with the result that the mass flow of the working fluid is increased. If, furthermore, liquid penetrates into the compressor, this causes an intensive internal cooling of the air during compression. The power consumption of the compressor and the final compressor temperature fall as a result. This leads to a rise in the net power output and to an improved efficiency of the gas turbine circulation process.
In addition, to increase the power output precisely in the case of high outside temperatures, other methods for cooling the suction-intake air of gas turbine groups are also known, for example evaporation coolers, in which the suction-intake air flows over moistened surfaces, or coolers with heat exchangers which discharge heat from the suction-intake air.
Below a specific temperature of the ambient air and, if appropriate—insofar as the cooling principle is not based on evaporation cooling—above a specific ambient atmospheric moisture, the cooling of the suction-intake air has to be deactivated, so that potentially harmful icing at the compressor inlet is avoided.
According to the prior art, the cooling of the suction-intake air serves primarily for increasing the power output beyond the basic maximum power of the gas turbine group which is available at a specific ambient temperature. If the ambient temperature lies above the critical icing temperature, cooling, for example liquid injection, is enabled and may be activated manually in the event of an increased power demand. As already indicated, the cooling of the suction-intake air and, in particular, the injection of liquid afford further advantages, for example an increase in efficiency and, in the case of a predetermined power output, a reduced temperature level of the overall circulation process. These potentials are utilized only incompletely in the manual activation of the cooling means.